Call switching system based on type of call

1. Apparats for use in a communication system having an analog loop said apparatus comprising: a loop driver for driving said analog loop, and terminal equipment devices interconnected with said analog loop, said loop driver for receiving an incoming call which incoming call includes an indication indicating whether said incoming call is a voice call or a non-voice call, constructing a call-type signal based on said indication, transmitting said call-type signal on said analog loop and, thereafter, placing a ringing signal distinct from said call-type signal on said analog loop; at least one switch for connection to said analog loop, said at least one switch having a port for connection to a type of terminal equipment, said type of terminal equipment comprising voice call terminal equipment or non-voice call terminal equipment, said switch for receiving said call-type signal on said analog loop and for disconnecting said port from said loop if said call-type signal indicates a type of call not compatible with said type of terminal equipment.

2. The apparatus of claim 1 wherein said at least one switch has a user input for selecting said type of terminal equipment for connection to said port.

3. The apparatus of claim 2 wherein said at least one switch is for, after disconnecting said port from said loop, connecting said port to said analog loop after a ringing signal which follows a call-type signal indicating a type of call not compatible with said type of terminal equipment ceases.

4. The apparatus of claim 1 wherein said switch is also for, if said port is disconnected from said loop, connecting said port to said loop if said call-type signal indicates a call which is compatible with said type of terminal equipment.

5. The apparatus of claim 4 wherein said at least one switch has three ports, one for connection to voice terminal equipment, one for connection to data terminal equipment, and one for connection to fax terminal equipment.

6. The apparatus of claim 5 wherein said at least one switch has a user input for selecting one of said ports for connection to said analog loop in the absence of any ringing signal or call-type signal on said analog loop.

7. The apparatus of claim 1 wherein said loop driver comprises a modulator for modulating said call-type signal onto said analog loop.

8. The apparatus of claim 7 wherein said switch comprises a demodulator and controller for demodulating said call-type signal received on said analog loop and for selectively disconnecting said at least one port in response to said demodulated signal.

9. Apparatus for use in a GSM system having a local analog loop comprising: a subscriber unit for driving said local analog loop, and terminal equipment devices interconnected with said local analog loop, said subscriber unit for receiving an out-of-band indication indicating whether any incoming call is a voice or a non-voice call, constructing a call-type signal based on said indication, transmitting said call-type signal on said analog loop and, thereafter, generating a ringing signal distinct from said call-type signal on said analog loop; at least one switch for coupling to said analog loop, said at least one switch having a port for connection to one type of terminal equipment, said one type of terminal equipment comprising voice call terminal equipment or non-voice call terminal equipment, said switch for receiving said call-type signal on said analog loop and for disconnecting said port from said loop if said call-type signal indicates a type of call not compatible with said one type of terminal equipment.

10. A method for use in a communication system having an analog loop driven by a loop driver, comprising: receiving at said loop driver an incoming call which incoming call includes an indication indicating whether said incoming call is a voice call or a non-voice call; placing a singing signal on said analog loop; based on said indication, transmitting a call-type signal, distinct from said ringing signal; on said analog loop; responsive to said call-type signal, disconnecting any port from said analog loop which is not intended for attachment wit terminal equipment compatible with a call-type indicated by said call-type signal.

11. The method of claim 10 including the step of, responsive to said call-type signal, connecting said port to said analog loop if said port is intended for attachment to terminal equipment of a type compatible with a call-type indicated by said call-type signal prior to placing said ringing signal on said analog loop, if said port is disconnected from said analog loop.

12. The method of claim 11 wherein said signal indicates whether said incoming call is a voice, data, or fax call.

13. A switch for an analog loop of a communication system, comprising: a port intended for connection to a type of terminal equipment, said type of terminal equipment comprising voice call terminal equipment or non-voice call terminal equipment; a demodulator and controller for receiving a call-type signal modulated on said analog loop and associated with a call, demodulating said call-type signal, and for, if said port is connected to said loop, disconnecting said port from said loop if said call-type signal indicates a type of call not compatible with the type of terminal equipment intended for connection to said port, and ensuring a connection between said analog loop and said port, if said call-type signal indicates a type of call compatible with the type of terminal equipment intended for connection to said port, thereby passing said call and a ring signal associated with said call distinct from said call-type signal to said port, and any interconnected terminal equipment.

14. A loop driver for a public switched telephone network (PSTN), comprising: a normally closed switch for interposing between a PSTN and an analog loop; a controller for opening said switch upon sensing a ringing cadence, determining a type of call based on said ringing cadence, passing a call-type indication to said analog loop, and closing said switch.

15. A method of driving an analog subscriber loop, said analog subscriber loop for driving terminal equipment devices interconnected with said analog subscriber loop, said method comprising: a) receiving a call including an indicator of a call type at an analog subscriber loop driver; b) placing a ring signal on said analog subscriber loop; c) modulating a signal indicative of said call type and distinct from said ring signal, on said analog subscriber loop, while all terminal equipment devices interconnected with said analog loop are on-hook.

16. A driver for driving an analog loop and terminal equipment interconnected with said analog loop, said driver comprising: a receiver for receiving a call including an indicator of a call type; a ring generator for placing a ring signal on said analog loop; a modulator for modulating a signal indicative of a type of call received at said analog loop driver, and distinct from a ring signal, on an analog loop interconnected with said analog loop driver, while all terminal equipment devices interconnected with said analog loop are on-hook.

17. The driver of claim 16, further comprising: a controller in communication with said modulator, said controller operable to sense a ringing cadence received from a telephone network interconnected with said driver, and pass a signal to said modulator corresponding to said ringing cadence, and wherein said signal indicative of a type of call, is formed based on said signal passed by said controller.

18. The driver of claim 17, further comprising: a switch disconnecting any subscriber loop and hence any terminal equipment device interconnected with said subscriber loop from said telephone network, in response to receiving a ring signal from said telephone network, said switch further operable to connect said loop to said telephone network, after said modulator has modulated said signal indicative of a type of call on said loop.

19. A telephony interface, for connection to an analog subscriber loop and a telephony equipment device, said analog subscriber loop for driving terminal equipment devices interconnected with said analog loop, said interface comprising: a demodulator for receiving a call-type signal associated with an incoming call and indicative of a call type of said incoming call, modulated on an analog subscriber loop connected to said interface, said call-type signal distinct from a ring signal on said analog subscriber loop and received prior to answering said incoming call; a switch in communication with said demodulator, and connecting said analog subscriber loop and a telephony equipment device interconnected with said interface, when said call-type signal indicates a pre-selected call type compatible with said terminal equipment device interconnected with said switch.

20. The interface of claim 19, further comprising a user input for selecting a call-type compatible with a terminal equipment device interconnected with said switch.

21. The interface of claim 19 wherein said switch has three ports, one for connection to voice terminal equipment, one for connection to data terminal equipment, and one for connection to fax terminal equipment, and wherein said switch connects a one of said ports compatible with a call type indicated by said call type signal.

22. The interface of claim 21, further comprising a user input for selecting one of said ports for connection to said analog loop in the absence of a call-type signal on said analog loop.

23. The interface of claim 19, wherein said switch disconnects said analog subscriber loop from said terminal equipment device interconnected with said interface, when said call-type signal indicates a call type incompatible with said terminal equipment device interconnected with said interface.

24. A method of interfacing voice or non-voice terminal equipment with an analog loop, said method comprising: receiving a call-type signal associated with a call on said analog loop, said call-type signal distinct from a ring signal on said analog loop; demodulating said call-type signal; responsive to said call-type signal indicating a call-type compatible with said terminal equipment, ensuring a connection between said analog loop and said terminal equipment to pass a ring signal distinct from said call-type signal, and said call to said terminal equipment; responsive to said call-type signal indicating a call-type incompatible with said terminal equipment, ensuing a disconnection between said analog loop and said terminal equipment.

25. Apparatus for use in a communications system having an analog loop, said apparatus comprising; a loop driver for driving said analog loop, and telephony equipment devices interconnected with said analog loop, said loop driver operable to: receive an incoming call including an indication indicating whether said incoming call is a voice call or a non-voice call; place a ringing signal on said analog loop; construct a call-type signal based on said indication, and distinct from said ringing signal; and transmit said call-type signal on said analog loop said apparatus further comprising at least one switch for connection to said analog loop, said at least one switch having a port for connection to a type of terminal equipment, said type of terminal equipment comprising voice call terminal equipment or non-voice call terminal equipment, said switch for receiving a call-type signal on said analog loop and for disconnecting said port from said loop if said call-type signal indicates a type of call not compatible with said type of terminal equipment.

26. The apparatus of clam 25, wherein said loop driver is further operable to transmit said call-type signal before placing said ringing signal on said analog loop.